DE10356000B4 - Silencer with integrated catalytic converter - Google Patents

Abstract

The silencer has a housing (2) with inlet manifold (6) and outlet pipe (7) and containing a catalytic converter element (10) whose inlet end (12) is in an inlet chamber (11)and whose outlet end (14) is in an outlet chamber (15) The outlet end (23) of the inlet manifold (6) communicates with the inlet chamber which is sealed from the outside and from the manifold and catalytic element so that during operation of the engine exhaust gas which passes through the inlet manifold into the inlet chamber leaves the latter solely through the catalytic element. Two or more catalytic converter elements can be arranged to allow parallel through-flow.

Description

The The present invention relates to a silencer with integrated catalyst for an exhaust system an internal combustion engine, in particular in a motor vehicle, with the features of the preamble of claim 1.

An exhaust system of an internal combustion engine is regularly provided with at least one muffler to reduce the noise emission of the internal combustion engine through the exhaust system. Furthermore, at least one catalytic converter is regularly arranged in the exhaust system of the internal combustion engine in order to reduce the pollutant emissions of the internal combustion engine. For the housing of the individual components of the exhaust system is often little space available, especially in motor vehicles. It is basically possible to arrange a catalyst space-saving within a muffler. Expediently, this may be a catalyst which is to be additionally installed in an exhaust system which is per se, such as, for example, a so-called SCR catalytic converter. With the aid of such an SCR catalyst, NO _x contents of the exhaust gases can be reduced to H ₂ O and N ₂ , if urea or ammonia is metered in controlled upstream of the SCR catalyst.

A muffler of the type mentioned is from the DE 37 29 477 A1 known and includes an integrated catalyst and is for an exhaust system of a Brennkraftma machine, in particular in a motor vehicle, suitable. The silencer comprises a housing which has an inlet funnel on the input side and an outlet tube on the output side. In the housing, a catalyst element is arranged, which is located with an inlet end in an inlet chamber and with an outlet end in an outlet chamber. In this case, an outlet end of the inlet funnel communicates with the inlet chamber, which is sealed to the outside and to the inlet funnel and the catalyst element so far that during operation of the internal combustion engine exhaust gas that passes through the inlet funnel into the inlet chamber leaves the inlet chamber exclusively through the catalyst element. In the known muffler, the inlet chamber forms an integral part of the housing.

From the DE 42 19 540 A1 For example, a catalyst is known whose housing has a double-walled construction in the region of a catalyst element.

The DE 102 09 557 A1 shows a muffler, in which a catalyst is integrated, which is arranged directly at the outlet end of an inlet pipe, without the interposition of an inlet space.

From the DE 101 23 360 A1 another muffler is known in which a catalyst can be arranged, wherein an inlet chamber is provided which forms a part of the housing of the muffler.

From the DE 39 40 747 C1 For example, a catalyst with flow guide elements is known, which are arranged directly in front of the catalyst element.

The present invention employs dealing with the problem, for a silencer of the aforementioned type to provide an improved embodiment in which in particular, the assembly of the muffler is simplified, wherein at the same time achievable an efficient sealing of the inlet chamber is.

This Problem is inventively the subject of the independent Claim solved. Advantageous embodiments are the subject of the dependent Claims.

The The present invention is based on the general idea, a Entry chamber, in which enter the muffler supplied exhaust gases and from which the exhaust gases enter at least one catalyst element, Furthermore hermetically seal. In this way, the exhaust gases, the inlet chamber leave only through the at least one catalyst element. Especially becomes a flow around or a bypass of the at least one catalyst element avoided. By the construction according to the invention Thus, a leak-free inlet chamber is provided, whereby the exhaust gas flow inevitably is passed through the at least one catalyst element. On This way it is ensured that in at least one catalyst element one possible high conversion of pollutants can take place. The effectiveness of in the silencer integrated catalyst is thereby significantly improved. Of the Silencer according to the invention differs thus basically from conventional silencers, where a hermetic seal of the entry area not is required.

For this beats the invention to form the inlet chamber in an inlet chamber housing, used as a separate component in the housing of the muffler is. Such a separate inlet chamber housing can be easily prefabricated and provided with the required tightness. For the silencer results thus a simplified design with improved sealing effect.

Within of the housing extends an outlet pipe, that on the output side of the case led out of this is. According to one preferred embodiment this outlet pipe extends in the case within a different level than the at least one catalyst element. In this way, a simplified construction for the silencer, since the outlet pipe in the level assigned to it arbitrarily, thus independently of the at least one catalyst element can be laid in the housing. On this way can be especially for the outlet pipe a required long length within of the housing be achieved for a desired Silencing effect is particularly advantageous.

While at a conventional one silencer an inlet floor or an outlet floor through flanging or by individual welds with a jacket of the housing is connected, the inlet chamber in a preferred embodiment the present invention by means of solder joints and / or welded joints be sealed, the a funnel and / or each catalyst element and / or the inlet chamber opposite the casing annular enclose. The sealing of the inlet chamber is here by a more expensive Connection technology realized, whereby the connection used but gets a double function, so the muffler Total is economically producible.

Further important features and advantages of the invention will become apparent from the Dependent claims, from the drawings and from the associated description of the figures the drawings.

It it is understood that the above and the following yet to be explained features not only in the specified combination, but also in other combinations or alone, without to leave the scope of the present invention.

One preferred embodiment The invention is illustrated in the drawings and is in the following description explains the same reference numerals to the same or functionally identical or similar Refer to components.

It show, in each case schematically,

1 to 3 in each case a longitudinal section through a silencer according to the invention, in different embodiments,

4 a cross section through the muffler,

5 a sectional view corresponding to the section lines V in 4 of the muffler.

Corresponding 1 has a silencer according to the invention 1 a housing 2 on, in particular, has a cylindrical shape. The housing 2 includes a coat 3 as well as an inlet floor 4 and an outlet floor 5 , In the area of the inlet floor 4 , so on the input side is the case 2 with an inlet funnel 6 equipped, extending from a not shown exhaust pipe to the housing 2 widens. In the area of the outlet floor 5 , so the output side is the case 2 with an outlet pipe 7 equipped, which can also lead to an exhaust pipe or its outlet end 8th (see. 5 ) forms the exhaust gas outlet of an exhaust line, not shown, in which the muffler 1 is installed. This exhaust line belongs to an internal combustion engine and their exhaust gases from their combustion chambers in the environment. Suitably, this internal combustion engine is arranged in a motor vehicle, in particular in a commercial vehicle.

In the muffler 1 is a catalyst 9 integrated. For this purpose, the muffler contains 1 in his case 2 at least one catalyst element 10 , In the preferred embodiment shown, several, here exemplarily six, catalyst elements 10 provided in its entirety the catalyst 9 form. Accordingly, the catalyst 9 in the figures, each marked with a brace. These catalyst elements 10 can optionally have a ceramic or metal substrate as support material.

The catalyst elements 10 are in the case 2 arranged so that they can be flowed through in parallel.

In the case 2 is an entrance chamber 11 formed over the inlet funnel 6 the exhaust gases are supplied. The catalyst elements 10 are with their entry ends 12 each to the inlet chamber 11 connected. In the present case, penetrate the catalyst elements 10 with their entry ends 12 a partition 13 which the entrance chamber 11 at an inlet funnel 6 closes opposite side. Here are the catalyst elements 10 through this partition 13 passed. This passage through the partition 13 is gas-tight and in particular realized by means of a solder joint or weld joint, not shown here, the annular and closed the respective catalyst element 10 along the partition 13 includes.

Each catalyst element 10 flows with its respective exit end 14 in an exit chamber 15 , on the one hand, from the outlet bottom 5 and this opposite of another partition 16 is limited. The catalyst elements 10 have at their exit ends 14 each an annular perforation 17 on. This design causes a damping of gas pulsations in the outlet chamber 15 , This makes it possible, the structure-borne noise excitation at the outlet bottom 5 to reduce.

Between the two partitions 13 and 16 ie between the inlet chamber 11 and the exit chamber 15 is a collection chamber 18 arranged, in which an entrance end 19 (see also 5 ) of the outlet tube 7 located. So that the exhaust gas from the outlet chamber 15 in the collection chamber 18 passes, is the partition wall arranged therebetween 16 permeable to gas, in particular perforated. Additionally or alternatively, this partition 16 also with at least one passage opening 20 (see. 4 ).

Is essential to the invention now that the inlet chamber 11 is designed gas-tight, so that via the inlet funnel 6 supplied exhaust exclusively through the catalyst elements 10 again from the entrance chamber 11 can escape. Due to the gas-tight design of the inlet chamber 11 may be the leakage of exhaust gas into the environment of the muffler 1 and a bypass of the catalyst elements 10 , so an escape into the collection chamber 18 be avoided. Such a hermetically sealed inlet chamber 11 is for a preferred application of the muffler 1 of particular importance, namely, when the catalyst integrated therein 9 designed as an SCR catalyst and is used to convert urea or ammonia, upstream of the muffler 1 is introduced into the exhaust system. For the design of an SCR catalyst 9 Accordingly, SCR catalyst elements 10 used.

By means of the abovementioned additives, the SCR technique, that is to say by selective catalytic reaction or reduction, can reduce the NO _x components in the exhaust gas to H ₂ O and N ₂ . So this SCR catalyst 9 works particularly effective and the admixed urea or the admixed ammonia does not enter the environment, is in the invention, the inlet chamber 11 designed leak-free. This is achieved for example by the fact that in the embodiments of the 1 and 2 the inlet funnel 6 with at least one annular and closed along the inlet floor 4 circumferential, not shown here weld joint or solder joint with the inlet bottom 4 connected is. Furthermore, the between inlet chamber 11 and collection chamber 18 arranged partition 13 annularly closed circumferentially sealed to the outside.

In the embodiments of the 1 and 2 is the entry chamber 11 in a separate inlet chamber housing 21 formed, which also in cross-section according to 4 is recognizable. This separate inlet chamber housing 21 as such is completely in the housing 2 of the muffler 1 used. The inlet chamber housing 21 also has a coat 22 and is the output side through the partition 13 locked. On the input side is the inlet chamber housing 21 through the inlet floor 4 closed, with the rest of the inlet floor 4 ' of the housing 2 connected, in particular tightly inserted therein. For closing the housing on the input side 2 is thus an additional, correspondingly shaped inlet bottom 4 ' required. Likewise, an embodiment is possible in which the inlet chamber housing 21 and the case 2 are verschlos sen by a common inlet bottom and / or at the inlet chamber housing 21 has its own outlet floor.

The separately manufactured inlet chamber housing 21 in particular can be easily prefabricated, whereby the desired tightness for the inlet chamber 11 is relatively inexpensive feasible. Appropriately, the inlet funnel 6 to this inlet chamber housing 21 grown, leaving an exit end 23 of the inlet funnel 6 in the entry chamber 11 empties.

In contrast, in the embodiment according to 3 the entry chamber 11 in one the exit end 23 of the inlet funnel 6 containing end portion 24 of the inlet funnel 6 educated. In other words, the catalyst elements 10 extend with their entry ends 12 to the exit end 23 of the inlet funnel 6 , In particular, according to 3 the inlet funnel 6 virtually the inlet bottom of the inlet chamber housing 21 make or dispensable. To here still a sufficient distribution of the catalyst elements 10 supplied exhaust gas flow to the individual catalyst elements 10 or to achieve their flow-through cross-sections, can in the inlet funnel 6 optionally a distributor and / or mixing element 25 be arranged, which is shown here with a broken line. This distributor and / or mixing element 25 Supports, for example, the expansion of the incoming exhaust gas flow and allows the most uniform possible flow of the individual inlet ends 12 the catalyst elements 10 , It is clear that such a distributor and / or mixing element 25 also in the embodiments of 1 and 2 in the inlet funnel 6 can be arranged.

In the embodiment according to 1 is the entry chamber 11 designed comparatively large volume, which in the inlet chamber 11 a relatively homogeneous mixing and a relatively uniform distribution of the incoming exhaust gases to the individual catalyst elements 10 re is alisierbar.

In contrast, in the embodiments of the 2 and 3 the entry chamber 11 smaller dimensions. In these embodiments is in the housing 2 in addition a damping chamber 26 formed in the one indicated by hatching damping material 27 is arranged. This damping chamber 26 is eg between the inlet chamber 11 and the exit chamber 15 and also expediently between the inlet chamber 11 and the collection chamber 18 arranged. For this purpose is another partition 28 provided, which the collection chamber 18 from the damping chamber 26 separates. If - as in the embodiment according to 2 - An inlet chamber housing 21 is provided, the damping chamber can 26 inside the case 2 also on the side of the inlet chamber housing 21 to the inlet floor 4 ' extend. This is for example due to a multi-layered construction of the muffler 2 allows for something very clear 4 evident. There is the housing 2 at least in the region of the inlet chamber housing 21 in two levels, namely in a catalyst level 29 and in an outlet tube plane 30 , divided. Within the catalyst level 29 is the catalyst 9 or are its catalyst elements 10 arranged while in the outlet tube level 30 the outlet pipe 7 is arranged. According to 4 extends the outlet pipe 7 thus below the catalyst 9 or below the catalyst elements 10 and thus also below the inlet chamber housing 21 if one exists. This construction results in a greater freedom for the design and installation of the outlet pipe 7 so that this can be optimized in particular with regard to its length.

Corresponding 5 extends the outlet pipe 7 starting at its entry end 19 with a first section 31 in the collection chamber 18 in a second section 32 in the damping chamber 26 and with a third section 33 back in the collection chamber 18 as well as in the exit chamber 15 from where the outlet pipe 7 out of the case 2 , through the outlet floor 5 exit and at the exit end 8th ends. The one in the collection chamber 18 arranged and the entrance end 19 having first section 31 is with a perforation 34 provided, which is schematically indicated here with a few breakthroughs. This perforation 34 allows the inflow of exhaust gas from the plenum 18 in the outlet pipe 7 in addition to the open entrance end 19 , The entry end 19 is relatively close to the partition 16 between collection chamber 18 and exit chamber 15 positioned, whereby a particularly large outlet tube length is achieved, what the damping effect of the muffler 1 improved in the low frequency range.

Furthermore, it is also in the damping chamber 26 extending second section 32 the outlet pipe 7 with a perforation 35 provided, which is also indicated only by some breakthroughs. It is noteworthy that the perforation 35 the outlet pipe 7 in the damping chamber 26 not for a gas exchange, but for a sound outlet from the outlet pipe 7 in the damping chamber 26 is provided. In this way, the airborne sound carried in the exhaust gas in the damping chamber 26 and there in the damping material 27 penetrate, whereby an effective damping of the airborne sound can be achieved. According to their different functions are the perforations 34 and 35 the two pipe sections 31 and 32 different dimensions. So are the opening cross sections at the perforation 34 of the first pipe section 31 inside the collection chamber 18 larger than those of the perforation 35 of the second pipe section 32 inside the damping chamber 26 ,

The silencer according to the invention 1 also has a reduced structure-borne sound radiation to the outside and an improved heat balance. This is achieved by a double-walled version of the housing 2 , In particular, the coat 3 double-walled, so with two single walls 3a and 3b designed, being between the individual walls 3a . 3b an insulation insert 36 is arranged. This insulation insert 36 is mainly used for thermal insulation and can also be designed to dampen sound. Analogous to this is also the inlet bottom 4 double-walled, so with two single walls 4a and 4b designed. It is also between the individual walls 4a and 4b of the inlet floor 4 a corresponding insulation insert 36 brought in. In a similar way is the outlet bottom 5 designed double-walled, being between the individual walls 5a and 5b the outlet floor 5 also a corresponding insulation insert 36 is introduced. According to the 1 and 2 is also the coat 22 of the inlet chamber housing 21 designed double-walled. Between the individual walls 22a and 22b of the coat 22 then there is again a corresponding insulation insert 36 , According to the 1 to 3 is also the inlet funnel 6 designed double-walled, so that a coat 37 of the inlet funnel 6 between his individual walls 37a and 37b again a suitable insulation insert 36 receives.

According to the 1 and 5 can the case 2 next to the inlet chamber housing 21 So essentially in the outlet tube level 30 another chamber 39 included by the adjacent damper chamber 26 through another partition 38 is disconnected. In this additional chamber 39 it may be another damper chamber, accordingly with damping material 27 can be filled. The partition 38 can be perforated. It essentially serves to fix the position of the outlet tube 7 and the inlet chamber housing 21 in the case 2 ,

The silencer according to the invention 1 with integrated catalyst 9 works as follows:
During operation of the internal combustion engine, the exhaust gases flow through the inlet funnel 6 into the entrance chamber 11 one. The exhaust gases may be enriched in a preferred application with urea or with ammonia. In the entrance chamber 11 The exhaust gases are distributed as evenly as possible at the inlet ends 12 the catalyst elements 10 , Because the entry chamber 11 According to the invention is designed leak-free, there is no other way for the exhaust gases, the inlet chamber 11 to leave. Thus, all the exhaust gases flow through the catalyst elements 10 ,

Through the catalyst elements 10 enter the exhaust gases in the outlet chamber 15 , From the exit chamber 15 The exhaust gases pass through the partition wall 16 in the collection chamber 18 , From the collection chamber 18 The exhaust gases pass through the entrance end 19 as well as through the perforation 34 in the outlet pipe 7 , Through the outlet pipe 7 the exhaust gases are removed from the housing 2 led out. The perforation 35 inside the sound-damping chamber 26 allows a sound into the damping material 27 , whereby in particular higher interference frequencies are absorbed.

Claims (15)

Silencer with integrated catalytic converter ( 9 ) for an exhaust line of an internal combustion engine, in particular in a motor vehicle, - with a housing ( 2 ), the input side an inlet funnel ( 6 ) and on the output side an outlet pipe ( 7 ), - wherein in the housing ( 2 ) at least one catalyst element ( 10 ), wherein - the catalyst element or elements ( 10 ) with an entry end ( 12 ) in an inlet chamber ( 11 ) and with an exit end ( 14 ) in an exit chamber ( 15 ) are arranged, - wherein an outlet end ( 23 ) of the inlet funnel ( 6 ) with the inlet chamber ( 11 ) communicates, - whereby the inlet chamber ( 11 ) to the outside and opposite the inlet funnel ( 6 ) and the catalyst element or elements ( 10 ) is sealed so far that during operation of the internal combustion engine exhaust gas, which through the inlet funnel ( 6 ) into the inlet chamber ( 11 ), the inlet chamber ( 11 ) exclusively by the catalyst element (s) ( 10 ) leaves, characterized in that the inlet chamber ( 11 ) in an inlet chamber housing ( 21 ) is formed as a separate component in the housing ( 2 ) is used. Silencer according to claim 1, characterized in that the outlet chamber ( 15 ) by a partition wall ( 16 ) with a collection chamber ( 18 ) communicates with an entry end ( 19 ) of the outlet pipe ( 7 ) in the collection chamber ( 18 ) is arranged. Silencer according to claim 1 or 2, characterized in that at least two parallel durchströmmare catalyst elements ( 10 ) are provided. Silencer according to one of claims 1 to 3, characterized in that in the inlet funnel ( 6 ) a distributor and / or mixing element ( 25 ) which directs the incoming exhaust gas to the inlet end (s) ( 12 ) of the catalyst element or elements ( 10 ). Silencer according to one of claims 1 to 4, characterized in that each catalyst element ( 10 ) at its exit end ( 14 ) an annular perforation ( 17 ) having. Silencer at least according to claim 2, characterized in that the partition wall ( 16 ) between exit chamber ( 15 ) and collection chamber ( 18 ) is perforated and / or at least one passage opening ( 20 ) contains. Silencer at least according to claim 2, characterized in that the collecting chamber ( 18 ) between the inlet chamber ( 11 ) and the exit chamber ( 15 ) is arranged. Silencer according to one of claims 1 to 7, characterized in that - in the housing ( 2 ) a damping chamber ( 26 ), the damping material ( 27 ), that a perforated section ( 32 ) of the outlet pipe ( 7 ) within the damping chamber ( 26 ). Silencer according to claim 8, characterized in that at least a part of the damping chamber ( 26 ) between the collection chamber ( 18 ) and the inlet chamber ( 11 ) is arranged. Silencer according to one of claims 2 to 9, characterized in that - the entry end ( 19 ) of the outlet pipe ( 7 ) near the partition ( 16 ) between exit chamber ( 15 ) and collection chamber ( 18 ), that the outlet pipe ( 7 ) within the collection chamber ( 18 ) is perforated. Silencer according to claims 8 and 10, characterized in that the perforation ( 34 ) of the outlet pipe ( 7 ) in the collection chamber ( 18 ) has larger opening cross-sections than the perforation ( 35 ) of the outlet pipe ( 7 ) in the damping chamber ( 26 ). Silencer according to one of claims 1 to 11, characterized in that the outlet pipe ( 7 ) in the housing ( 2 ) within another level ( 30 ) extends as the at least one catalyst element ( 10 ). Silencer according to one of claims 1 to 12, characterized in that the at least one catalyst element ( 10 ) is an SCR catalyst element. Silencer according to one of claims 1 to 13, characterized in that the inlet funnel ( 6 ) and / or the housing ( 2 ) and / or the inlet chamber housing ( 21 ) and / or one of the inlet funnel ( 6 ) interspersed inlet floor ( 4 ) of the housing ( 2 ) and / or from the outlet tube ( 7 ) permeated outlet bottom ( 5 ) of the housing ( 2 ) double-walled with insulation insert ( 36 ) is configured. Silencer according to one of claims 1 to 14, characterized in that the inlet chamber ( 11 ) is sealed by means of solder joints and / or by means of welded joints, which the inlet funnel ( 6 ) and / or each catalyst element ( 10 ) and / or the inlet chamber ( 11 ) opposite the housing ( 2 ) surround annularly.